The present invention relates to novel herbicidally active substituted N-pyridyl-nitrogen heterocycles, processes for their preparation, compositions comprising these compounds, and their use for controlling weeds, especially in crops of useful plants such as, for example, cereals, maize, rice, cotton, soya, oil seed rape, sorghum, sugar cane, sugar beet, sunflowers, vegetables, plantation crops and forage plants, or for inhibiting the growth of plants, and for nonselective weed control.
N-phenyl- and n-pyridyl-pyrazole compounds and N-pyridyltetramethylene triazolidine diones which are herbicidally active are described, for example, in EP-A-0 370 332, DE-A-3 917 469, DE-A-19 518 054, DE-A-19 530 606, U.S. Pat. No. 5,306,694 and U.S. Pat. No. 4,406,689. Also known as herbicides are N-pyridylimides, N-(2-pyridyl)pyridazinones and N-phenyluracils, as described, for example, in WO 92/00976, JP-A-58-213 776 and EP-A-0 438 209. N-(phenyl)tetrahydroimidazoles having herbicidal activity are described, for example, in U.S. Pat. No. 5,112,383.
There have now been found novel substituted N-pyridyl-nitrogen heterocycles which have herbicidal and growth-inhibitory properties.
The present invention thus relates to compounds of the formula I 
xe2x80x83in which
A xe2x95x90Nxe2x80x94 or 
R1 is hydrogen, fluorine, chlorine, bromine or methyl;
R2 is C1-C4alkyl, C1-C4haloalkyl, halogen, R6Oxe2x80x94, nitro, amino or cyano;
R3 is halogen, nitro, amino, R4NHxe2x80x94, R4R5Nxe2x80x94, azido or CIS(O)2xe2x80x94;
R4 and R5 independently of one another are C1-C8alkyl, C3-C8alkenyl, C3-C8alkynyl, C3-C6cycloalkyl, C1-C8haloalkyl, C3-C8haloalkenyl, HCOxe2x80x94, C1-C4alkylcarbonyl, C1-C4haloalkylcarbonyl, C1-C4alkylsulfonyl, C1-C4haloalkylsulfonyl, benzyl or benzyl which is mono- to trisubstituted on the phenyl ring by halogen, C1-C4alkyl or C1-C4haloalkyl; or
R4 and R5 together with the N atom to which they are bonded form a saturated or unsaturated heterocyclic ring which contains O, N or S as further hetero atoms and which can be substituted by halogen, C1-C3alkyl, C1-C3haloalkyl, C1-C3alkoxy, C1-C4alkoxycarbonyl, C1-C3alkylS(O)n1xe2x80x94, nitro or cyano; or
R3 is R6Oxe2x80x94;
R6 is hydrogen, C1-C8alkyl, C3-C8alkenyl, C3-C8alkynyl, C3-C6cycloalkyl, C1-C8haloalkyl, cyano-C1-C8alkyl, C3-C8haloalkenyl, hydroxy-C1-C4alkyl, C1-C4alkoxy-C1-C4alkyl, C3-C6alkenyloxy-C1-C4alkyl, C3-C6alkynyloxy-C1-C4alkyl, C1-C4alkoxy-C1-C4alkoxy-C1-C4alkyl, C1-C4alkylthio-C1-C4alkyl, C1-C8alkylcarbonyl, C1-C8alkoxycarbonyl, C3-C8alkenyloxycarbonyl, benzyloxy-C1- or xe2x80x94C2alkyl, benzylcarbonyl, benzyloxycarbonyl, phenyl,phenyl-C2-C8alkyl, benzyl, pyridyl, pyrimidinyl, pyrazinyl or pyridazinyl, it being possible for these aromatic and heteroaromatic rings to be optionally mono- to trisubstituted by halogen, C1-C4alkyl or C1-C4haloalkyl; or
R6 is R7X1C(O)xe2x80x94C1-C8alkyl- or 
X1 is oxygen, sulfur or 
R7 is hydrogen, C1-C8alkyl, C3-C8alkenyl, C3-C8alkynyl, C3-C6cycloalkyl, C1-C8haloalkyl, C3-C8haloalkenyl, C1-C4alkoxy-C1-C4alkyl, C3-C6alkenyloxy-C1-C4alkyl, C1-C4alkylthio-C1-C4alkyl, phenyl, phenyl which is mono- to trisubstituted by halogen, C1-C4alkyl or C1-C4haloalkyl, or benzyl or benzyl which is mono- to trisubstituted on the phenyl ring by halogen, C1-C4alkyl or C1-C4haloalkyl;
R8 is hydrogen, C1-C8alkyl, C3-C8alkenyl, C3-C8alkynyl, C3-C6cycloalkyl, C1-C8haloalkyl or benzyl; or
R3 is R9S(O)n1xe2x80x94;
n1 is 0, 1 or 2;
R9 is C1-C8alkyl, C3-C8alkenyl, C3-C8alkynyl, C3-C6cycloalkyl, C1-C8haloalkyl, carboxy-C1-C4alkyl, C1-C4alkoxycarbonyl-C1-C4alkyl, benzyloxycarbonyl-C1-C4alkyl, C1-C4alkylthio-C(O)xe2x80x94C1-C4alkyl, C3-C5alkenyloxycarbonyl-C1-C4alkyl, C1-C4alkylaminocarbonyl-C1-C4alkyl, di-C1-C4alkylaminocarbonyl-C1-C4alkyl, C3-C5alkenylaminocarbonyl-C1-C4alkyl, C3-C8haloalkenyl, C1-C4alkoxy-C1-C4alkyl, C3-C6alkenyloxy-C1-C4alkyl, C1-C4alkylthio-C1-C4alkyl, phenyl, phenyl which is mono- to trisubstituted by halogen, C1-C4alkyl or C1-C4haloalkyl, or benzyl or benzyl which is mono- to trisubstituted on the phenyl ring by halogen, C1-C4alkyl or C1-C4haloalkyl, and, if n1 is 0,
R9 is additionally hydrogen, C1-C8alkylcarbonyl, R10X2C(O)xe2x80x94 or R10X2C(O)xe2x80x94C1xe2x80x94 or xe2x80x94C2alkyl;
X2 is oxygen, sulfur or 
R10 is hydrogen, C1-C8alkyl, C3-C8alkenyl, C3-C8alkynyl, C3-C6cycloalkyl, C1-C8haloalkyl, C3-C8haloalkenyl, C1-C4alkoxy-C1-C4alkyl, C3-C6alkenyloxy-C1-C4alkyl, C1-C4alkylthio-C1-C4alkyl, phenyl, phenyl which is mono- to trisubstituted by halogen, C1-C4alkyl or C1-C4haloalkyl, or benzyl or benzyl which is mono- to trisubstituted on the phenyl ring by halogen, C1-C4alkyl or C1-C4haloalkyl;
R11 is hydrogen, C1-C8alkyl or C3-C8alkenyl; or
R3 is R12R13NS(O)2xe2x80x94;
R12 is hydrogen, C1-C8alkyl, C2-C8alkenyl, C3-C8alkynyl or C3-C6cycloalkyl;
R13 is hydrogen, C1-C8alkyl, C3-C8alkenyl, C3-C8alkynyl, C1-C8haloalkyl, C1-C4alkoxy-C1-C4alkyl, C1-C4alkylcarbonyl, C1-C4haloalkylcarbonyl, benzyl, benzoyl, or benzyl or benzoyl which are mono- to trisubstituted on the phenyl ring by halogen, C1-C4alkyl or C1-C4haloalkyl;
W is a group 
xe2x80x83or 
R14 is C1-C3alkyl, C1-C3haloalkyl or amino;
R15 is C1-C3haloalkyl, C1-C3alkyl-S(O)n2xe2x80x94, C1-C3haloalkyl-S(O)n2xe2x80x94 or cyano; or
R15 and R14 together form a C3 or C4alkylene bridge which can be substituted by halogen, C1-C3haloalkyl or cyano;
n2 is 0, 1 or 2;
R16 is hydrogen, C1-C3alkyl, halogen, C1-C3haloalkyl or cyano; or
R16 and R15 together form a C3 or C4alkylene bridge which can be substituted by halogen, C1-C3haloalkyl or cyano;
R17 is hydrogen, C1-C3alkyl, halogen or cyano; R18 is C1-C3haloalkyl; or
R18 and R17 together form a C3 or C4alkylene or C3 or C4alkenylene bridge, both of which can be substituted by halogen, C1-C3alkyl or C1-C3haloalkyl;
R19 is hydrogen, C1-C3alkyl or halogen; or
R19 and R18 together form a C3 or C4alkylene or C3 or C4alkenylene bridge, both of which can be substituted by halogen, C1-C3alkyl or C1-C3haloalkyl;
R20 and R21 independently of one another are hydrogen or C1-C4alkyl; or
R20 and R21 together are a group of 
R25 and R26 independently of one another are C1-C4alkyl; or
R25 and R26 together form a C4 or C5alkylene bridge;
R22 is hydrogen or C1-C3alkyl; or
R22 and R21 together form a C3-C5alkylene bridge which can be interrupted by oxygen and substituted by halogen, C1-C4alkyl, C1-C3haloalkyl, C2-C4alkenyl, C1-C3alkylcarbonyloxy, C1-C3alkoxycarbonyl, C1-C3alkylsulfonyloxy, hydroxyl or xe2x95x90O;
R23 and R24 independently of one another are hydrogen or C1-C3alkyl; or
R23 and R24 together form a C2-C5alkylene bridge which can be interrupted by oxygen, sulfur, xe2x80x94C(O)xe2x80x94 or xe2x80x94S(O)2xe2x80x94; and
X3, X4, X5, X6, X7, X8 and X9 independently of one another are oxygen or sulfur, and the agrochemically tolerated salts and stereoisomers of these compounds of the formula I.
In the abovementioned definitions, halogen is to be understood as meaning iodine, preferably fluorine, chlorine and bromine.
The alkyl, alkenyl and alkynyl groups in the definitions of substituents can be straight-chain or branched, and this also applies to the alkyl, alkenyl and alkynyl moiety of the alkylcarbonyl, alkylcarbonyloxy, alkoxycarbonyl, alkenyloxycarbonyl, alkenyloxyalkyl, alkynyloxyalkyl-, alkylS(O)n2xe2x80x94, alkylsulfonyloxy, alkylthioalkyl, alkoxyalkyl, alkoxyalkoxyalkyl, alkylamino, dialkylamino, phenylalkyl and R7X1C(O)xe2x80x94C1-C8alkyl groups. Alkyl groups, are, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl and the various isomeric pentyl, hexyl, heptyl and octyl radicals. Preferred are methyl, ethyl, n-propyl, iso-propyl and n-butyl.
Examples which may be mentioned of alkenyls are vinyl, allyl, methallyl, 1-methylvinyl, but-2-en-1-yl, pentenyl, 2-hexenyl, 3-heptenyl and 4-octenyl, preferably alkenyl radicals having a chain length of 3 to 5 carbon atoms.
Examples of alkynyls which may be mentioned are propargyl, 1-methylpropargyl, 3-butinyl, but-2-yn-1-yl, 2-methylbutin-2-yl, but-3-yn-2-yl, 1-pentinyl, pent-4-yn-1-yl, 2-hexinyl, 3-heptin-1-yl and 4-octin-1-yl, preferably alkynyl radicals having a chain length of 3 or 4 carbon atoms.
Suitable as haloalkyl are alkyl groups which are mono- or polysubstituted, in particular mono- to trisubstituted, by halogen, halogen being specifically iodine and in particular fluorine, chlorine and bromine, for example fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, 2-fluoroethyl, 2,2-difluoroethyl, 2-chloroethyl, 2,2-dichloroethyl, 2,2,2-trifluoroethyl, 2,2,2-trichloroethyl and pentafluoroethyl.
Suitable as haloalkenyl are alkenyl groups which are mono- or polysubstituted by halogen, halogen being specifically bromine, iodine and in particular fluorine and chlorine, for example 2- and 3-fluoropropenyl, 2- and 3-chloropropenyl, 2- and 3-bromopropenyl, 2,3,3-trifluoropropenyl, 2,3,3-trichloropropenyl, 4,4,4-trifluorobut-2-en-1-yl and 4,4,4-trichlorobut-2-en-1-yl. Preferred amongst the alkenyl radicals which are mono-, di- or trisubstituted by halogen are those which have a chain length of 3 or 4 carbon atoms. The alkenyl groups can be substituted by halogen on saturated or unsaturated carbon atoms.
Alkylsulfonyl is, for example, methylsulfonyl, ethylsulfonyl, propylsulfonyl, iso-propylsulfonyl, n-butylsulfonyl, iso-butylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl; preferably methylsulfonyl and ethylsulfonyl.
Haloalkylsulfonyl is, for example, fluoromethylsulfonyl, difluoromethylsulfonyl, trifluoromethylsulfonyl, chloromethylsulfonyl, trichloromethylsulfonyl, 2-fluoroethylsulfonyl, 2,2,2-trifluoroethylsulfonyl and 2,2,2-trichloroethylsulfonyl.
Haloalkenylsulfonyl is, for example, 2- and 3-fluoropropenylsulfonyl, 2- and 3-chloropropenylsulfonyl, 2- and 3-bromopropenylsulfonyl, 2,3,3-trifluoropropenylsulfonyl, 2,3,3-trichloropropenylsulfonyl, 4,4,4-trifluoro-but-2-en-1-yl-sulfonyl and 4,4,4-trichlorobut-2-en-1-yl-sulfonyl.
Alkylcarbonyl is, in particular, acetyl and propionyl.
Haloalkylcarbonyl is, in particular, trifluoroacetyl, trichloroacetyl, 3,3,3-trifluoropropionyl and 3,3,3-trichloropropionyl.
Cyanoalkyl is, for example, cyanomethyl, cyanoethyl, cyanoeth-1-yl and cyanopropyl.
Hydroxyalkyl is, for example, 2-hydroxyethyl, 3-hydroxypropyl and 2,3-dihydroxypropyl.
Alkoxyalkyl is, for example, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, n-propoxymethyl, n-propoxyethyl, iso-propoxymethyl and iso-propoxyethyl.
Alkenyloxyalkyl is, for example, allyloxyalkyl, methallyloxyalkyl and but-2-en-1-yl-oxyalkyl.
Alkynyloxyalkyl is, for example, propargyloxyalkyl and 1-methylpropargyloxyalkyl.
Alkoxycarbonyl is, for example, methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, iso-propoxycarbonyl and n-butoxycarbonyl, preferably methoxycarbonyl and ethoxycarbonyl.
Alkenyloxycarbonyl is, for example, allyloxycarbonyl, methallyloxycarbonyl, but-2-en-1-yl-oxycarbonyl, pentenyloxycarbonyl and 2-hexenyloxycarbonyl.
The cycloalkyl radicals which are suitable are as substituents are, for example, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.
Alkylthio is, for example, methylthio, ethylthio, propylthio and iso-propylthio.
Alkylthioalkyl is, for example, methylthioethyl, ethylthioethyl, methylthiopropyl and ethylthiopropyl.
L in the reagents of the formulae V, VII, XXI, XXX, XXXIIIa and XXXIIIb in reaction schemes 1, 2, 4, 6 and 7 is a leaving group such as, for example, halogen, for example chlorine, bromine or iodine, or sulfate, for example CH3S(O)2Oxe2x80x94 or 
L1 in the reagent of the formula XXII (reaction scheme 4) is a leaving group such as, for example, HOS(O)2Oxe2x80x94, 
R4 and R5 together with the N atom to which they are bonded form a saturated or unsaturated heterocyclic ring which can contain O, N or S as further heteroatoms, for example the following heterocycles: 
xe2x80x83and 
it being possible for these heterocycles additionally to be substituted by halogen, C1-C3alkyl, C1-C3haloalkyl, C1-C3alkoxy, C1-C4alkoxycarbonyl, C1-C3alkylS(O)n1xe2x80x94, nitro or cyano.
Corresponding meanings may also be assigned to the substituents in composite definitions such as, for example, alkenyloxycarbonylalkyl, alkenylaminocarbonylalkyl, alkylthio-C(O)-alkyl, haloalkylS(O)n2, R4NHxe2x80x94, R4R5Nxe2x80x94, R10X2C(O)xe2x80x94, R6Oxe2x80x94, R9S(O)n1xe2x80x94, R10X2C(O)xe2x80x94, R10X2C(O)xe2x80x94C1 or -C2alkyl and R12R13NS(O)2xe2x80x94.
In the definition of R6, the group 
means that the R7X1C(O)-substituted C1-C8alkylene chain is additionally phenyl-substituted on one of the 8 carbon atoms, it being possible for the phenyl ring to be mono- to trisubstituted by halogen, C1-C4alkyl or C1-C4haloalkyl and for the alkylene chain to be straight-chain or branched, for example methylene, ethylene, methylethylene, propylene, 1-methylpropylene and butylene.
In the definitions cyanoalkyl, carboxyalkyl, alkylcarbonyl, alkylcarbonyloxy, alkoxycarbonyl, alkenyloxycarbonyl and haloalkylcarbonyl, the carbonyl carbon atom is not included in the lower and upper limits of carbon atoms given in each case.
The invention also extends to the salts which the compounds of the formula I which have an acidic hydrogen, in particular the derivatives having carboxyl and sulfonamide groups (for example carboxyl-substituted alkyl and alkylene groups (R6), alkylS(O)2NHxe2x80x94 and haloalkylS(O)2NHxe2x80x94 substituted pyridyl groups (R3)), can form with bases. These salts are, for example, alkali metal salts such as, for example, sodium salts and potassium salts; alkaline earth metal salts such as, for example, calcium salts and magnesium salts; ammonium salts, i.e. unsubstituted ammonium salts and mono- or polysubstituted ammonium salts such as, for example, triethylammonium salts and methylammonium salts; or salts with other organic bases.
Amongst the alkali metal hydroxides and alkaline earth metal hydroxides, examples of salt formers which must be emphasized are the hydroxides of lithium, sodium, potassium, magnesium or calcium, but in particular those of sodium and potassium. Suitable salt formers are described, for example, in WO 97/41112.
Possible examples for amines which are suitable for ammonium salt formation are ammonia and also primary, secondary and tertiary C1-C18alkylamines, C1-C4hydroxyalkylamines and C2-C4alkoxyalkylamines, for example methylamine, ethylamine, n-propylamine, iso-propylamine, the four butylamine isomers, n-amylamine, iso-amylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, methylethylamine, methyl-iso-propylamine, methylhexylamine, methyinonylamine, methylpentadecylamine, methyloctadecylamine, ethylbutylamine, ethylheptylamine, ethyloctylamine, hexylheptylamine, hexyloctylamine, dimethylamine, diethylamine, di-n-propylamine, di-iso-propylamine, di-n-butylamine, di-n-amylamine, di-iso-amylamine, dihexylamine, diheptylamine, dioctylamine, ethanolamine, n-propanolamine, iso-propanolamine, N,N-diethanolamine, N-ethylpropanolamine, N-butylethanolamine, allylamine, n-butenyl-2-amine, n-pentenyl-2-amine, 2,3-dimethylbutenyl-2-amine, di-butenyl-2-amine, n-hexenyl-2-amine, propylenediamine, trimethylamine, triethylamine, tri-n-propylamine, tri-iso-propylamine, tri-n-butylamine, tri-iso-butylamine, tri-sec-butylamine, tri-n-amylamine, methoxyethylamine and ethoxyethylamine; heterocyclic amines such as, for example, pyridine, quinoline, iso-quinoline, morpholine, thiomorpholine, piperidine, pyrrolidine, indoline, quinuclidine and azepine; primary arylamines such as, for example, anilines, methoxyanilines, ethoxyanilines, o,m,p-toluidines, phenylenediamines, benzidines, naphthylamines and o,m,pchloroanilines; but in particular triethyl amine, iso-propylamine and di-iso-propylamine.
The salts of the compounds of the formula I which have basic groups, in particular basic pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl and pyrazolyl rings or of the derivatives having amino groups such as, for example, alkylamino and dialkylamino groups in the definition of R2 or R3 are, for example, salts with inorganic and organic acids such as, for example, hydrohalic acids such as hydrofluoric acid, hydrochloric acid, hydrobromic acid or hydriodic acid, and also sulfuric acid, phosphoric acid, nitric acid and organic acids such as acetic acid, trifluoroacetic acid, trichloroacetic acid, propionic acid, glycolic acid, thiocyanic acid, citric acid, benzoic acid, oxalic acid, formic acid, benzenesulfonic acid, p-toluenesulfonic acid and methanesulfonic acid.
The presence of an asymmetric carbon atom in the compounds of the formula I, for example in the substituent R2 or R3=OR6, in which R6 is a branched alkyl, alkenyl, haloalkyl or alkoxyalkyl group, or R3=S(O)n1R9, in which, for example, n1=1 and/or R9 is a branched alkyl, alkenyl, haloalkyl or alkoxyalkyl group, results in the fact that the compounds may occur not only in optically active single isomers, but also in the form of racemic mixtures. The present invention is to be understood as meaning, by active ingredients of the formula I, not only the pure optical antipodes but also the racemates or diastereomers.
If an aliphatic Cxe2x95x90C double bond is present, geometric isomerism may occur. The present invention also extends to these isomers.
Preferred compounds of the formula I are those in which R2 is methyl, halogen, hydroxyl, nitro, amino or cyano; R3 is nitro, amino, R4NHxe2x80x94, R4R5Nxe2x80x94, azido or CIS(O)2xe2x80x94; R9, if n1 is 0, is additionally hydrogen, C1-C8alkylcarbonyl or R10X2C(O)xe2x80x94; R13 is hydrogen, C1-C8alkyl, C3-C8alkenyl, C3-C8alkynyl, C1-C8haloalkyl, C1-C4alkoxy-C1-C4alkyl, C1-C4alkylcarbonyl, C1-C4haloalkylcarbonyl, benzoyl or benzoyl which is mono- to trisubstituted on the phenyl ring by halogen, C1-C4alkyl or C1-C4haloalkyl; and R4, R5, R10 and X2 have the meanings given under formula I.
Other preferred compounds of the formula I are those in which W is the group 
and R14, R15, R16, X3 and X4 have the meanings given under formula I. Especially preferred amongst those are compounds in which R14 is methyl, R15 is trifluoromethyl, R16 is hydrogen, and X3 and X4 are oxygen.
Other preferred compounds of the formula I are those in which W is the group 
and R17, R18, R19 and X5 have the meanings given under formula I. Especially preferred compounds are, in particular, those in which R17 and R19 independently of one another are hydrogen or C1-C3alkyl; R18 is trifluoromethyl, and X5 is oxygen.
Other preferred compounds of the formula I are those in which W is the group 
R20, R21 and R22 have the meanings given under formula I, and X6 and X7 are oxygen. Especially preferred amongst these compounds are, in particular, those in which R21 and R22 together form a C4alkylene bridge which can be substituted by halogen, hydroxyl or xe2x95x90O.
Other preferred compounds of the formula I are those in which W is the group 
R23 and R24 have the meanings given under formula I, and X8 and X9 are oxygen. Especially preferred amongst these compounds are those in which R23 and R24 together form a C3 or C4alkylene bridge.
Other preferred compounds of the formula I are those in which R1 is fluorine or chlorine, R2 is chlorine, bromine or cyano, R3 is R6Oxe2x80x94, and R6 is C1-C4alkyl, C1-C4alkoxy-C1-C4alkyl, C3-C6alkenyloxy-C1-C4alkyl, C3-C6alkenyl, C3-C6alkynyl or benzyl. Especially important amongst these compounds are, in particular, those in which R2 is chlorine or cyano.
Preferred compounds of the formula I, are, furthermore, those in which R2 is methyl, halogen, hydroxyl, nitro, amino, cyano, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy.
The process according to the invention for the preparation of compounds of the formula I is carried out in a manner similar to known processes and comprises, to prepare those compounds of the formulae Ia, Iaa, Ib and Ibb
in which R1, R2, R6 and W have the meanings given under formula I, R2 preferably being halogen, oxidizing, for example, a compound of the formula III 
in a suitable solvent to first give the compound of the formula IV 
subsequently subjecting this compound to a rearrangement reaction in an inert solvent in the presence of an anhydride or of antimony pentachloride (so-called Katada reaction) and, after aqueous workup, obtaining the compounds of the formulae Ib and Ibb
the radicals R1, R2 und W in the compounds of the formulae IIII, IV, Ib and Ibb having the abovementioned meanings, and converting these compounds with a compound of the formula V
R6xe2x80x94Lxe2x80x83xe2x80x83(V)
in which R6 has the meaning given under formula I, with the exception of R6 being hydrogen, and L is a leaving group such as, for example, halogen, in particular chlorine, bromine or iodine, or a sulfonate, in particular CH3S(O)2Oxe2x80x94 or 
in the presence of an inert solvent and of a base to give the isomeric compounds of the formulae Ia, Iaa and II 
in which R1, R2, R6 and W have the abovementioned meanings, subsequently removing the compounds of the formula Ia and Iaa from the pyridone by-product of the formula II and, if appropriate, further functionalizing the compounds as defined for R3 under formula I.
The process according to the invention for the preparation of compounds of the formula I is carried out by a method similar to known processes and comprises, to prepare those compounds of the formula Ic
in which R1, R2, R9, n1 and W have the meanings given under formula I, halogenating, for example, a compound of the formula Ib
in which R1, R2 and W have the abovementioned meanings, with a halogenating agent such as, for example, phosphorus oxychloride, if appropriate in the presence of a base and of a suitable solvent and obtaining the compound of the formula VI 
the radicals R1, R2 and W in the compounds of the formulae Ib and VI having the abovementioned meanings and Hal in the compound of the formula VI being fluorine, chlorine or bromine, converting these compounds with a sulfur reagent such as, for example, hydrogen sulfide or its alkaline earth metal salt in the presence of a base and of a suitable solvent to give the compound of the formula Id
subsequently reacting this compound with a compound of the formula VII
R9xe2x80x94Lxe2x80x83xe2x80x83(VII)
in which R9 has the meaning given under formula I with the exception of R9 being hydrogen, and L is a leaving group, if appropriate in the presence of a solvent and of a base, to give the compound of the formula Ic
in which R1, R2, R9 and W have the abovementioned meanings and n1 is 0, and, if appropriate, oxidizing this compound to give the compound of the formula Ic, in which n1 is 1 or 2.
The compounds of the formula Ic in which n1 is 2 and R9 is an unsubstituted or substituted C1-C4alkyl or phenyl canxe2x80x94like the compounds of the formula VI which are substituted in the 6-position by halogenxe2x80x94be used as intermediates for the preparation of compounds of the formula I by substituting the group R9S(O)2xe2x80x94 with Oxe2x80x94, Nxe2x80x94 or S-nucleophiles. The substitution of an alkylsulfonyl or phenylsulfonyl group on pyridine rings with nucleophiles is described, for example, in Bull. Chem. Soc. Jp. 60 (1987), 335 and 343, Het. 24 (1986), 3019 and J. Het. Chem. 22 (1985),1583.
The process according to the invention for the preparation of compounds of the formula I is carried out by a method similar to known processes and comprises, to prepare those compounds of the formula I 
in which A, R1, R2 and W have the meanings given under formula I and R3 is R6Oxe2x80x94, R9S(O)n1xe2x80x94, amino, R4NHxe2x80x94 or R4R5Nxe2x80x94, halogenating, for example, a compound of the formula III or IV 
and obtaining the compound of the formula VI 
xe2x80x83and subsequently either converting this compound
a) with a compound of the formula IX, if appropriate in the presence of a base and of an inert solvent, or IXa
R6OHxe2x80x83xe2x80x83(IX)
xe2x80x83or
[R6xe2x80x94O]xe2x88x92tMt+xe2x80x83xe2x80x83(IXa)
where R6 has the meaning given under formula I, M in the compound of the formula IXa is an alkali metal atom or alkaline earth metal atom and t is 1 or 2 or
b) with a compound of the formula X, if appropriate in the presence of a base and of an inert solvent, or Xa
R9SHxe2x80x83xe2x80x83(X)
xe2x80x83or
[R9xe2x80x94S]xe2x88x92tMt+xe2x80x83xe2x80x83(Xa)
where R9has the meanings given under formula I, M in the compound of the formula Xa is an alkali metal atom or alkaline earth metal atom and t is 1 or 2, to give first the compound of the formula Ic
in which R1, R2, R9 and W have the abovementioned meanings and n1 is 0, and, if appropriate, oxidizing this compound to give the compound of the formula Ic in which n1 is 1 or 2, for example using hydrogen peroxide, or
reacting the compound of the formula VI
c) with a compound of the formula XI
[R9xe2x80x94S(O)2]xe2x88x92M1+xe2x80x83xe2x80x83(XI)
in which R9 has the abovementioned meaning and M1+ is an alkali metal ion or
d) with a compound of the formula XII, if appropriate in the presence of a base and of an inert solvent, or XIIa
R4NH2xe2x80x83xe2x80x83(XII)
xe2x80x83or
R4NHxe2x88x92M1+xe2x80x83xe2x80x83(XIIa)
in which R4 has the meaning given under formula I and M1+ is an alkali metal ion or
e) with a compound of the formula XII, if appropriate in the presence of a base and of an inert solvent, or XIIIa
xe2x80x83R4R5NHxe2x80x83xe2x80x83(XIII)
xe2x80x83or
R4R5Nxe2x88x92M1+xe2x80x83xe2x80x83(XIIIa)
in which R4 and R5 have the meanings given under formula I and M1+ is an alkali metal ion, and, if appropriate, subsequently oxidizing the compounds of the formula I (A xe2x95x90Nxe2x80x94) which have been obtained by the above variants a) to e) 
The process according to the invention for the preparation of compounds of the formula I is carried out by a method similar to known processes such as described, for example, in EP-A-0 438 209 or DE-OS-19 604 229 and comprises, to prepare those compounds of the formula Ie
in which R1, R2, R3, R14, R15, R16, X3 and X4 have the meanings given under formula I and R3 is additionally hydrogen, converting, for example a compound of the formula XIV 
in which R1, R2 and R3 have the abovementioned meanings and L2 is a leaving group such as, for example, halogen, e.g. fluorine, chlorine or bromine, or C1-C4alkyl- or phenylsulfonyl group or a C1-C4alkyl- or phenylsulfonyloxy group in the presence of an inert solvent and of ammonia, if appropriate in an autoclave, at temperatures of xe2x88x9210 to 180xc2x0 C. to give the compound of the formula XV 
converting this compound in the presence of a base and of a solvent
a) with chloroformic ester of the formula XVI 
in which X3 has the meaning given under formula I
to give the compound of the formula XVII 
b) with oxalyl chloride, phosgene or thiophosgene to give the compound of the formula XVIII 
subsequently subjecting the compound of the formula XVII or XVIII to a cyclization reaction with an enamine derivative of the formula XIX 
in which R15 and R16 have the meanings given under formula I and X4 is oxygen in the presence of 0.1-1.5 equivalents of a base in an inert solvent, and obtaining the compound of the formula XX 
in which R1, R2, R3, R15, R16, X3 and X4 have the abovementioned meanings, further reacting this compound in the presence of an inert solvent and a base with
a) a compound of the formula XXI
R14xe2x80x94Lxe2x80x83xe2x80x83(XXI),
in which R14 is C1-C3alkyl or C1-C3haloalkyl and L is a leaving group or
b) with a hydroxylamine derivative of the formula XXII
NH2xe2x80x94L1xe2x80x83xe2x80x83(XXII)
in which L1 is a leaving group, and, if appropriate, treating the compounds of tho formula Ie in which X4 is oxygen, which have been obtained by the above variants a) and b), with a thionizing reagent (X4 sulfur).
The process according to the invention for the preparation of compounds of the formula I is carried out by a method similar to known processes and comprises, to prepare those compounds of the formula If
in which R1, R2, R3, R17, R18, R19 and X5 have the meanings given under formula I and R3 is additionally hydrogen, for example, either
a) converting a compound of the formula XIV 
in which R1, R2 and R3 have the abovementioned meanings and L2 is a leaving group such as, for example, halogen, e.g. fluorine, chlorine or bromine, or C1-C4alkyl- or phenylsulfonyl group or a C1-C4alkyl- or phenylsulfonyloxy group, with hydrazine, preferably in a protic solvent, to give the compound of the formula XXIII 
further reacting this compound with a compound of the formula XXIV or XXIVa 
in which R17 and R18 have the meanings given under formula I and Hal in the compound of the formula XXIVa is chlorine and bromine, or
b) first diazotizing, advantageously with exclusion of water, a compound of the formula XV 
in which R1, R2 and R3 have the abovementioned meanings, subsequently further reacting this compound with a compound of the formula XXVI 
in which R17 and R18 have the abovementioned meanings,
and obtaining the compound of the formula XXV 
which is cyclized, if appropriate in the presence of a base such as, for example, 4-dimethylaminopyridino, and of a compound of the formula XXVII 
in which R19 has the abovementioned meaning and X5 is oxygen, and, if appropriate, treating this compound with a thionizing reagent (X5 sulfur).
The process according to the invention for the preparation of compounds of the formula I is carried out by a method similar to known methods such as described in, for example, EP-A-0 272 594, EP-A-0 493 323, DE-A-3 643 748, WO 95/23509, U.S. Pat. No. 5,665,681 and U.S. Pat. No. 5,661,109 and comprises, to prepare those compounds of the formula Ig
in which R1, R2, R3, R20, R21, R22, X6 and X7 have the meanings given under formula I and R3 is additionally hydrogen, for example, either reacting
a) in the presence of a solvent or of a base, a compound of the formula XVIIa 
xe2x80x83or
b) if appropriate in a suitable solvent, a compound of the formula XVIIa 
the radicals R1, R2, R3 and X7 in the compounds of the formulae XVIIa and XVIIIa having the abovementioned meaning,
with a compound of the formula XXVIII 
in which R20, R21, R22 and X6 have the abovementioned meanings and obtaining the compound of the formula XXIX 
subjecting this compound to cyclization in the presence of a suitable solvent and of a base, and, subsequently, if appropriate,
c) if R22 is hydrogen, reacting this compound with a compound of the formula XXX
R22xe2x80x94Lxe2x80x83xe2x80x83(XXX)
in which R22 is C1-C3alkyl and L is a leaving group and,
d) if X6 and/or X7 are oxygen, treating this compound with a thionizing reagent (X6 and/or X7 sulfur).
The process according to the invention for the preparation of compounds of the formula I is carried out by a method similar to known methods such as described in, for example, EP-A-0 210 137, DE-A-2 526 358, EP-A-0 075 267 and EP-A-0 370 955 and comprises, to prepare those compounds of the formula Ih
in which R1, R2, R3, R23, R24, X8 and X9 have the meanings given under formula I and R3 is additionally hydrogen, reacting, for example,
a) in the presence of a solvent and of a base, a compound of the formula XVIIb 
xe2x80x83or
b) if appropriate in a suitable solvent, a compound of the formula XVIIIb 
in which the radicals R1, R2, R3 and X9 in the compounds of formulae XVIIb and XVIIIb having the abovementioned meanings
with a compound of the formula XXXI 
in which R23, R24 and X8 have the abovementioned meanings, and obtaining the compound of the formula XXXII 
subjecting this compound to cyclization in the presence of a suitable solvent and of a base, and subsequently if appropriate,
c) if R23 and/or R24 are hydrogen, further reacting this compound with a compound of the formula XXXIIIa or XXXIIIb
R23xe2x80x94Lxe2x80x83xe2x80x83(XXXIIIa)
or
R24xe2x80x94Lxe2x80x83xe2x80x83(XXXIIIb)
in which R23 and R24 independently of one another are C1-C3alkyl and L is a leaving group, or with a Michael acceptor, and,
d) if X8 and/or X9 are oxygen, treating this compound with a thionizing reagent (X8 and/or X9 sulfur).
The process according to the invention for the preparation of compounds of the formula I is carried out by a method similar to known processes such as described, for example, in J. Het. Chem. 15 (1978), 1221, and comprises reacting, for example, a compound of the formula XIV 
in which R1, R2 and R3 have the meanings given under formula I, R3 is additionally hydrogen and L2 is a leaving group such as, for example, halogen, e.g. fluorine, chlorine or bromine, or a C1-C4alkyl- or penyl-sulfonyl group or a C1-C4alkyl- or phenyl-sulfonyloxy group with a compound of the formula W01, W02, W03 or W04 
in which the radicals R14 to R24 and X3 to X9 have the meanings given under formula I, if appropriate in the presence of a suitable solvent and of a base, and subjecting the resulting compounds of the formula I (A xe2x95x90Nxe2x80x94) to oxidation 
A further process according to the invention for the preparation of specifically substituted compounds of the formula I is carried out by a manner similar to known processes and comprises, to prepare those compounds of the formula Ii
in which R1 is hydrogen or fluorine, R2 is cyano, R3 is halogen, amino, R4NHxe2x80x94, R4R5Nxe2x80x94, azido, R6Oxe2x80x94 or R9S(O)n1xe2x80x94 and R4, R5, R6, R9, n1, A and W have the meanings given under formula I, reacting, for example, a compound of the formula XIVa 
in which L2 is a leaving group such as, for example, chlorine, bromine or C1-C4alkylsulfonyl, R3 is chlorine or bromine and R1 has the abovementioned meaning, with a compound of the formula W01, W02, W03 or W04 
in which the radicals R14 to R24 and X3 to X9 have the meanings given under formula I, or salts of these, if appropriate in a suitable organic solvent and in the presence of a base, such as, for example, carbonates, e.g. potassium carbonate, at elevated temperature or at the reflux temperature of the solvent used to give the compound of the formula Ii
in which R3 is chlorine or bromine and R1 and W have the abovementioned meanings, and subjecting this compound to a nucleophilic aromatic substitution reaction, either
a) with a compound of the formula IX, if appropriate in the presence of a base and of an inert solvent, or IXa
R6OHxe2x80x83xe2x80x83(IX)
or
[R6xe2x80x94O]xe2x88x92tMt+xe2x80x83xe2x80x83(IXa)
in which R6 has the meaning given under formula I, M in the compound of the formula IXa is an alkali metal atom or alkaline earth metal atom and t is 1 or 2, or
b) with a compound of the formula X, if appropriate in the presence of a base and of an inert solvent, or Xa
R9SHxe2x80x83xe2x80x83(X)
or
[R9xe2x80x94S]xe2x88x92tMt+xe2x80x83xe2x80x83(Xa)
in which R9 has the meaning given under formula I, M in the compound of the formula Xa is an alkali metal atom or alkaline earth metal atom and t is 1 or 2, and first converting it into the compound of the formula Ii
in which R1, R9 and W have the abovementioned meanings and n1 is 0 and, if appropriate, oxidizing this compound to give the compound of the formula Ii in which n1 is 1 or 2, for example using hydrogen peroxide, or
c) with a compound of the formula XI
[R9xe2x80x94S(O)2]xe2x88x92M1+xe2x80x83xe2x80x83(XI)
in which R9 has the abovementioned meanings and M1+ is an alkali metal ion, or
d) with a compound of the formula XII, if appropriate in the presence of a base and of an inert solvent, or XIIa
R4NH2xe2x80x83xe2x80x83(XII)
or
R4NHxe2x88x92M1+xe2x80x83xe2x80x83(XIIa)
in which R4 has the meaning given under formula I and M1+ is an alkali metal ion or
e) with a compound of the formula XIII, if appropriate in the presence of a base and of an inert solvent, or XIIIa
R4R5NHxe2x80x83xe2x80x83(XIII)
or
R4R5Nxe2x88x92M1+xe2x80x83xe2x80x83(XIIIa)
in which R4 and R5 have the meanings given under formula I and M1+ is an alkali metal ion, and, if appropriate, subsequently oxidizing the compounds of the formula Ii (A xe2x95x90Nxe2x80x94) obtained by the above variants a) to e) 
The preparation of compounds of the formulae Ia, Iaa, Ib and Ibb
in which R1, R2, R6 and W have the meanings given under formula I, R2 preferably being halogen, is illustrated in reaction scheme 1 which follows. 
The pyridine N-oxides of the formula IV (reaction scheme 1) can be prepared by known methods (for example Org. Synth. 4 (1963), 828; ibid. 3 (1955), 619; U.S. Pat. No. 3,047,579; and B. Iddon and H. Suschitzky in xe2x80x9cPolychloroaromatic Compoundsxe2x80x9d, Editor H. Suschitzky, Plenum Press, London 1974, page 197), expediently by reacting the pyridine derivatives of the formula III with oxidants such as, for example, organic peracids, for example m-chloroperbenzoic acid (MCPBA), peracetic acid and pertrifluoroacetic acid, or aqueous hydrogen peroxide solution or hydrogen peroxide/urea adduct together with carboxylic acids and/or carboxylic anhydrides, or inorganic peracids, for example pertungstic acid (Caro""s acid). Suitable solvents are, for example, water, organic acids such as, for example, acetic acid and trifluoroacetic acid, halogenated hydrocarbons such as, for example, dichloromethane and 1,2-dichloroethane, esters, such as, for example, ethyl acetate, ethers such as, for example, tetrahydrofuran and dioxane, or mixtures of these. The reaction temperatures are in the range of xe2x88x9220xc2x0 C. to 100xc2x0 C., depending on the solvent or solvent mixture used.
The 6-hydroxypyridine derivatives of the formula Ib can be prepared by known methods (for example Quart. Rev. 10 (1956), 395; J. Am. Chem. Soc. 85 (1963), 958; and J. Org. Chem. 26 (1961), 428), expediently by means of subjecting the pyridine N-oxides of the formula IV to a rearrangement reaction in the presence of anhydrides, for example acetic anhydride, trifluoroacetic anhydride and methanesulfonic anhydride, in a suitable inert solvent such as, for example, halogenated hydrocarbons, e.g. dichloromethane and 1,2-dichloroethane, amides, e.g. N,N-dimethylformamide and 1-methyl-2-pyrrolidone (NMP), if appropriate in the presence of sodium acetate. The reaction temperatures are generally in the range of from xe2x88x9230xc2x0 C. to 80xc2x0 C. The same reaction, in particular where R2 is chlorine, also gives the isomeric 6-chloro-5-hydroxypyridine derivatives of the formula Ibb by further rearranging the N-oxides of the formula IV. The primary products 6-O-acyl- or 6-O-sulfonylpyridines can be hydrolyzed readily by means of aqueous work-up of the reaction mixture to give the desired 6-hydroxypyridines of the formula Ib. Similarly to Tetrahedron 37 (1981), 187, antimony pentachloride (Katada reaction) is also suitable for the above rearrangement reaction as further variant. The same applies to the isomeric 5-O-acylated derivatives. If appropriate, the isomers of the formula Ib or Ibb can be separated by known methods. However, they may also be reacted further as isomer mixture, the compounds of the formulae Ia, Iaa and II being obtained under identical reaction conditions.
The subsequent alkylation can be effected by known methods (for example Org. Prep. Proced. Int. 9 (1977), 5; J. Org. Chem. 35 (1970), 2517; ibid. 32 (1967), 4040; and Tetrahedron Lett. 36 (1995), 8917, and Preparation Example H6), expediently with the aid of an alkylating reagent of the formula V. As a rule, alkylation leads to an isomer mixture composed of the compounds of the formulae Ia and, if appropriate, Iaa (O-alkylation) and II (N-alkylation). A further variant of preparing the alkylation products is to react the hydroxypyridines of the formula Ib or Ibb with an alcohol of the formula R6OH in which R6 has the meaning given under formula I in an inert solvent such as, for example, tetrahydrofuran, dioxane or dimethoxyethane in the presence of a phosphine such as, for example, triphenylphosphine and an azodicarboxylic acid derivative such as, for example, diethyl azodicarboxylate. Such Mitsunobu reactions are described, for example, in Tetrahedron Letters 1994, 2819.
Suitable solvents are, for example, alcohols, e.g. methanol, ethanol and isopropanol, amides, e.g. N,N-dimethylformamide (DMF) and 1-methyl-2-pyrrolidone (NMP), sulfoxides, e.g. dimethyl sulfoxide (DMSO) and sulfones, e.g. sulfolane, or mixtures of these with water, ethers, e.g. diethyl ether, tert-butyl methyl ether, dimethoxyethane (DME), dioxane and tetrahydrofuran (THF), esters, e.g. ethyl acetate, ketones, e.g. acetone and methyl ethyl ketone, and hydrocarbons, e.g. n-hexane, toluene and xylenes. Suitable bases are organic and inorganic bases such as, for example, alkali metal alkoxides, e.g. sodium mothoxida, sodium ethoxide and potassium tert-butoxide, trialkylammonium hydroxides, trialkylammonium halides, e.g. triethylammonium iodide, alkali metal and alkaline earth metal hydrides, e.g. sodium hydride together with lithium bromide (2 equivalents), alkali metal carbonates, e.g. potassium carbonate, alkali metal hydroxides, e.g. sodium hydroxide and potassium hydroxide, and caesium fluoride. The reaction temperatures for the alkylation are in the range of from xe2x88x9220xc2x0 C. to reflux temperature of the solvent used, preferably 0xc2x0 C. to 100xc2x0 C. The isomers of the formulae Ia, Iaa, Ibb and II can be separated readily by silica gel chromatography or fractional crystallization.
If appropriate, the desired pyridine derivatives of the formulae Ia, Iaa and Ibb, which have been separated from the by-product of the formula II, can readily be functionalized further by known methods in accordance with the definition of R3 under formula I.
The preparation of the compounds of the formula Ic
in which R1, R2, R9, n1 and W have the meanings given under formula I is illustrated in reaction scheme 2 which follows. 
In accordance with reaction scheme 2, the 6-halopyddines of the formula VI can be obtained from the corresponding 6-hydroxypyridines of the formula Ib by means of halogenation, for example by means of phosphorus oxychloride or phenyl dichlorophosphate, if appropriate in the presence of a base in an inert solvent, by methods similar to xe2x80x9cPyridine and its Derivativesxe2x80x9d, Part 2, Editor E. Klingsberg, New York 1961, page 326 et seq. The 6-halopyridines of the formula VI can be converted into the corresponding 6-mercaptopyridines of the formula Id by a method similar to known processes (for example as described in xe2x80x9cMethoden der Organischen Chemiexe2x80x9d [Methods in Organic Chemistry] (Houben-Weyl), Volume E/b, Heteroarene part 2, Georg Thieme Verlag Stuttgart, 1992, page 286 et seq.) using a suitable sulfur reagent such as, for example, hydrogen sulfide or its alkali metal salt, or thiourea in the presence of an inert solvent and of a base such as, for example, tertiary amines, alkali metal and alkaline earth metal hydroxides, or the corresponding alkali metal or alkaline earth metal oxides. The 6-mercaptopyridine derivative of the formula Id or its alkali metal salt is subsequently reacted with an alkylating reagent of the formula VII in which L is a leaving group, if appropriate in the presence of a base and of a suitable solvent, to give the 6-alkylmercapto derivative of the formula Ic. If appropriate, the thioethers of the formula Ic (n1=0) can be converted into the sulfoxides or sulfones Ic (n1=1 or 2) by known methods using an oxidant such as, for example, hydrogen peroxide, sodium periodate or m-chloroperbenzoic acid (m-CPBA) in an inert solvent such as, for example, dichloromethane. If appropriate, the reaction may also be stopped at the sulfoxide level.
The preparation of the compounds of the formula I in which A, R1, R2 and W have the meanings given under formula I and R3 is R6Oxe2x80x94, R9S(O)n1xe2x80x94, amino, R4NHxe2x80x94 or R4R5Nxe2x80x94 is illustrated in reaction scheme 3 which follows. 
The 6-halopyridines of the formula VI can be obtained readily from the corresponding pyridine N-oxides of the formula IV or else from the pyridine derivatives of the formula III in accordance with reaction scheme 3 by known standard methods by means of halogenation, for example using phosphorus oxychloride or phosphorus oxybromide. The reactive 6-halopyridines of the formula VI, in turn, can be reacted either
a) with an alcohol of the formula IX, if appropriate in the presence of a base and of an inert solvent, or with the corresponding alkali metal alkoxide of the formula IXa,
b) with a thiol of the formula X, if appropriate in the presence of a base and of an inert solvent, or with the corresponding alkali metal thiolate of the formula Xa,
c) with an alkali metal sulfinate of the formula XI, or
d) and e) with an excess of ammonia, with an amine of the formula XII or XIII, if appropriate in the presence of a base and of an inert solvent, or with the corresponding alkali metal salt of the formula XIIa or XIIIa
to give the desired compounds of the formula I in which R3 is either R6Oxe2x80x94, R9S(O)n1xe2x80x94, amino, R4NHxe2x80x94 or R4R5Nxe2x80x94 by methods similar to known nucleophilic substitution reactions. The 6-mercaptopyridines of the formula I obtained in accordance with variant b) in which R3 is R9S(O)n1 and n1 is 0 can be converted, if appropriate, by known oxidation methods, for example using hydrogen peroxide, organic peracids, sodium perborate (NaBO3), (NH4)2Ce(NO3)6, sodium periodate (NaIO4) or manganese dioxide (MnO2) to give the compounds of the formula I in which R3 is R9S(O)n1xe2x80x94 and n1 is 1 or 2. Such oxidations are described, for example, in xe2x80x9cOxidations in Organic Chemistryxe2x80x9d, Editor M. Hudlicky, ACS Monograph 186, Washington D.C., 1990. The resulting sulfonyl derivatives of the formula I in which R3 is R9S(O)n1 and n1 is 2 can be further derivatized in accordance with the definition of R3 by known methods, for example by nucleophilic aromatic substitution.
The above reactions in accordance with variants a), b), d) and e) are carried out with the non-deprotonated reagents of the formulae IX, X, XII and XIII, preferably in the presence of a base such as, for example, alkali metal hydroxides, alkaline earth metal hydroxides, alkaline earth metal oxides, alkali metal hydrides, e.g. sodium hydride, alkoxides, e.g. potassium tert-butoxide, quaternary ammonium hydroxides or tertiary amines, in a suitable inert solvent. Compounds of the formula I in which R3 is nitro can be f) either obtained directly by means of nitration and separation of undesired position-isomeric nitro derivatives, g) obtained readily by means of oxidizing the amino group of the corresponding 6-aminopyridine derivative of the formula I (R3 amino), or) can be obtained by a method similar to what has been described, for example, in xe2x80x9cOxidations in Organic Chemistryxe2x80x9d, Editor M. Hudlicky, ACS Monograph 186, Washington D.C., 1990, from the corresponding pyridine azides 
xe2x80x83or from the corresponding amines by oxidation, for example with an alkali metal peroxodisulfate or ammonium peroxodisulfate, for example in concentrated sulfuric acid as solvent at reaction temperatures of from xe2x88x9220xc2x0 to +30xc2x0 C. Compounds of the formula I in which R3 is an amino group (NH2) can furthermore be obtained by rearranging corresponding acetamides (R3=xe2x80x94OCH2CONH2) in the presence of a base, such as, for example, alkali metal carbonates, in an inert solvent such as, for example, dimethyl sulfoxide at temperatures of from 70xc2x0 to 150xc2x0 C.
Compounds of the formula I in which R2 or R3 is an amino group (NH2) can furthermore also be obtained by reducing the corresponding azides. For example, these azides can be prepared by a Mitsunobu reaction from the hydroxyintermediates, hydrazoic acid (HN3), a phosphine such as, for example, triphenylphosphine and an azo compound such as, for example, diethyl azodicarboxylate in an inert solvent. Such reactions are described, for example, in Synthesis 1992, 367.
The other compounds which come under the scope of the formula I can be prepared readily by methods similar to known standard processes taking into consideration the chemical reactivities of the pyridyl moiety and of the pyridyl -(Heterocyclyl)-W moiety (groups W1 to W4).
The preparation of the compounds of the formula Ie
in which R1, R2, R3, R14, R15, R16, X3 and X4 have the meanings given under formula I and R3 is additionally hydrogen is illustrated in reaction scheme 4 which follows. 
A multiplicity of known standard processes such as described, for example, in EP-A-0 438 209 and DE-OS-19 604 229 (R15 cyano) is suitable for the preparation of the compounds of the formula Ie according to the invention. Reaction scheme 4 shows a selection of suitable preparation methods, the choice of reaction routes and reagents depending on the reactivities of the substituents at the intermediate levels. For example, starting by reacting a compound of the formula XIV with ammonia in an inert solvent, if appropriate in an autoclave, at temperatures of xe2x88x9210 to 180xc2x0 C., the aminopyridine of the formula XV can be obtained. The latter can be converted, in the presence of a base and of a solvent, either
a) with chloroformic ster of the formula XVI (X3 oxygen or sulfur) to give a pyridylcarbamate of the formula XVII, or
b) with oxalyl chloride, phosgene (X3 oxygen) or thiophosgene (X3 sulfur) to give an iso(thio)cyanate of the formula XVIII. Such reactions are described, for example, in Angew. 1971, 407.
The carbamate and the iso(thio)cyanate of the formulae XVII and XVIII can be cyclized in the presence of the enamine derivative of the formula XIX in an inert solvent to give the urecil derivative of the formula XX, the reaction of the iso(thio)cyanate of the formula XVIII advantageously being carried out in the presence of 0.1-1.5 equivalents of a base such as, for example, sodium hydride, potassium tert-butoxide or alkaline earth metal oxide or alkaline earth metal hydroxide, for example barium hydroxide. The desired compounds of the formula Ie can be obtained by standard processes by converting the uracils of the formula XX in the presence of an inert solvent and at least 1 equivalent of a base, for example alkali metal carbonate, e.g. potassium carbonate,
c) with an alkylating agent of the formula XXI to give the N-alkyl derivative of the formula Ie (R14 alkyl), or
d) by a method similar to WO 97/05116 with a hydroxylamine derivative of the formula XXII, in which L1 is a leaving group, such as, for example, HOS(O)2Oxe2x80x94, 
for example 2,4-dinitrophenyl-hydroxylamine or hydroxylamine-O-sulfonic acid, to give the N-amino derivative of the formula Ie (R14 amino). The thiono derivatives of the formula Ie (X3, X4 sulfur) can be obtained by means of thionation, for example with phosphorus pentasulfide or Lawesson reagent.
The preparation of the compounds of the formula If
in which R1, R2, R3, R17, R18, R19 and X5 have the meanings given under formula I and R3 is additionally hydrogen is illustrated in reaction scheme 5 which follows. 
The compounds of the formula If can be prepared by known methods, for example in accordance with reaction scheme 5 by reacting a 2-halopyridine derivative of the formula XIV with hydrazine, preferably in a protic solvent such as, for example, alcohols, by a method similar to GB-A-2 230 261 to give the 2-hydrazino derivative of the formula XXIII. The latter is reacted with a diketone of the formula XXIV by a method similar to DE-OS-19 754 348 or a dihaloketone of the formula XXIVa by a method similar to WO 97/07104 to give the hydrazone derivative of the formula XXV. The subsequent cyclization which yields the desired compound of the formula If is carried out in the presence of the phosphorane derivative of the formula XXVII, if appropriate in the presence of a base, for example 4-dimethylaminopyridine. In the event that, in the compound of the formula If, X5 is O, the product may subsequently be thionized by a method similar to what has been described under reaction scheme 4 (X5 S). In accordance with reaction scheme 5, the hydrazone derivative of the formula XXV may also be obtained via diazotization, preferably with exclusion of water, and subsequent coupling with the keto acid of the formula XXVI (Japp-Klingemann reaction, similar to DE-OS-19 754 348), starting from the 2-aminopyridine derivative of the formula XV.
The preparation of the compounds of the formula Ig
in which R1, R2, R3, R20, R21, R22, X6 and X7 have the meanings given under formula I and R3 is additionally hydrogen is illustrated in reaction scheme 6 which follows. 
The compounds of the formula Ig can be prepared similarly to known methods such as described, for example, in EP-A-0 272 594, EP-A-0 493 323, DE-A-3 643 748, WO 95/23509, U.S. Pat. Nos. 5,665,681 or 5,661,109. In accordance with reaction scheme 6, for example, either
a) a carbamate derivative of the formula XVIIa in the presence of a solvent and of a base or
b) an iso(thio)cyanate of the formula XVIIa, if appropriate in a suitable solvent,
may be cyclized with an amino acid derivative of the formula XXVIII via the compound of the formula XXIX in the presence of a base and of a suitable solvent to give the compound of the formula Ig. In the event that, in the compound of the formula Ig, R22 is hydrogon and X6 and/or X7 are oxygen, the product can, if appropriate, be subsequently alkylated with an alkylating agent of the formula XXX on the free N atom of the hydantoin ring and the ring carbonyl group can be thionated (X6 and/or X7 sulfur). In the starting compounds of the formulae XVIIa and XVIIIa in reaction scheme 6, R3 may also be hydrogen. Functionalization in accordance with the definition of the substituent R3 in the compounds of the formula Ig may then be carried out by processes similar to those given in reaction schemes 1 to 3.
The preparation of the compounds of the formula Ih 
in which R1, R2, R3, R23, R24, X8 and Xa have the meanings given under formula I and R3 is additionally hydrogen is illustrated in reaction scheme 7 which follows. 
The compounds of the formula Ih can be prepared similarly to known processes such as described, for example, in EP-A-0 210 137, DE-OS-2 526 358, EP-A-0 075 267 or EP-A-0 370 955. In accordance with reaction scheme 7, for example, either
a) a carbamate derivative of the formula XVIIb in the presence of a solvent and of a base, or
b) an iso(thio)cyanate of the formula XVIIIb, if appropriate in a suitable solvent,
may be cyclized with a carbazate of the formula XXXI via the compound of the formula XXXII in the presence of a base and of a suitable solvent to give the compound of the formula Ih. In the event that, in the compound of the formula Ih, R23 and/or R24 are hydrogen and X8 and/or X9 are oxygen, the product can subsequently be alkylated with an alkylating reagent of the formula XXXIIIa or XXXIIIb on the free N-atoms and the ring carbonyl group can be thionated with the thionating reagent (X8 and/or X9 sulfur). To prepare compounds of the formula Ih in reaction scheme 7 in which R23 and R24 together form an alkylene bridge which is interrupted by, for example, xe2x80x94C(O)xe2x80x94 or xe2x80x94S(O)2xe2x80x94, for example the compound of the formula Ih, in which R23 and R24 are hydrogen can be reacted with a suitable Michael acceptor, such as, for example, CH2xe2x95x90CHxe2x80x94C(O)CH3, CH2xe2x95x90CHxe2x80x94S(O)2CH3 or CH2xe2x95x90CHxe2x80x94S(O)2xe2x80x94CHxe2x95x90CH2 and the resulting Michael adducts can be functionalized further.
The compounds of the formulae Ie, If, Ig and Ih in the preceding reaction schemes 4 to 7 in which X4, X5, X7 and X9 are O and R3 is hydrogen can subsequently be functionalized, for example as shown in reaction schemes 1 to 3, to give the compounds of the formulae Ie, If, Ig and Ih in which R3 has the meaning given under formula I.
In accordance with reaction scheme 8 which follows, the compounds of the formula I may also be obtained expediently directly by substituting a 2-halopyridine of the formula XIV or XIVa (R2xe2x95x90CN) with the desired heterocycles W01 to W04 or salts thereof (for example alkali metal salts), if appropriate in the presence of a suitable solvent and of a base (variant a)). Similar reactions are described, for example, in J. Het. Chem. 15, (1978), 1221. In some cases it may be expedient to couple the heterocyclic group W1 to W4, for example as shown in variant b) in reaction scheme 8 with reference to W1, to the pyridyl moiety by means of direct alkylation with an imino-ether-modified heterocycle of the formula W001. 
L2 in the compound of the formula XIV in reaction scheme 8 is a leaving group such as, for example, halogen or a C1-C4alkyl or phenyl-sulfonyl group.
The heterocyles of formula W01 in reaction scheme 8 above, wherein R14 is C1-C3alkyl (e.g. methyl), R15 is C1-C3haloalkyl (e.g. CF3), R16 is hydrogen and X3 and X4 are oxygen, are obtained either according to WO 98/08824 or by the reaction sequence as follows:
An enamine derivative of formula XXXIV 
wherein R14 is C1-C3alkyl, R15 is C1-C3haloalkyl and R27 is C1-C4alkyl, C1- or C2haloalkyl or optionally substituted benzyl, is converted in the presence of chlorocarbonyl isocyanate (CICONCO) in inert organic solvents to the compound of formula XXXV 
the ester function of which is then transferred to the corresponding carboxylic acid function as represented by compound of formula XXXVI 
which then is decarboxylated to yield the compound of formula W01 
the radicals R14, R15, R27, X3, X4 and R16 in the compounds of formulae XXXV, XXXVI and W01, having the abovementioned meaning. This reaction sequence is novel and therefore instant invention also relates to this method of preparation.
Above reaction sequence is illustrated in reaction scheme 9 which follows. 
According to reaction scheme 9 above the enamine derivative of formula XXXIV, wherein R14 and R15 are as defined and R27 is C1-C4alkyl (e.g. t-butyl), C1-C2haloalkyl (e.g. 2,2,2-trichloroethyl) or optionally substituted benzyl (e.g. p-methoxybenzyl) is reacted with chlorocarbonyl isocyanate (CICONCO) in inert sovents such as dichloromethane at temperatures in the range of from xe2x88x9230xc2x0 C. to +8xc2x0 C. to obtain the pyrimidine derivative of formula XXXV. The carboxylic ester function COOR27 of compound of formula XXXV is then cleaved for example by hydrolysis or hydrogenolysis to yield the corresponding carboxylic acid function of compound of formula XXXVI according to the following methods as described in xe2x80x98Protective Groups in Organig Synthesisxe2x80x99, Editor Th. Greene, New York, 1981; and Houben-Weyl, Band E5, xe2x80x98Carbonsxc3xa4uren und Carbonsxc3xa4urederivatexe2x80x99, Stuttgart, 1985:
treatment with an acid (formic acid containing catalytic amounts of sulfuric acid as described in Houben-Weyl above, p. 227) if R27 in compound of formula XXXV is alkyl or benzyl;
treatment with formic acid, trifluoroacetic acid or HBr if R27 in compound of formula XXXV is t-butyl or benzyl;
treatment with tin (Zn) in acetic acid if R27 in compound of formula XXXV is 2,2,2-trichloroethyl;
treatment with an oxidant such as ceric ammonium nitrate in water/acetonitril if R27 in compound of formula XXXV is 4-methoxybenzyl;
cleavage by hydrogenolysis (H2/appropriate catalyst such as Pdxe2x80x94C in inert solvent) if R27 in compound of formula XXXV is benzyl or substituted benzyl;
or by enzymatic cleavage (Ann. Rep. Med. Chem. 19, 263 (1984); Angew. 24, 617 (1985)).
Decarboxylation of the carboxylic acid derivative of formula XXXVI to the uracil compound of formula W01, wherein R16 is hydrogen is achieved finally by heating net or in inert solvents such as decaline or quinoline with or without additional catalysts such as Cu(O) or Cu(I)-salts such as CuCl.
The compounds of the formulae XIV, XIVa and XV which are not already known can be prepared by known methods such as described in, for example, DE-A-3 917 469; WO 97/07114; WO 92/00976; JP-A-58-213 776; EP-A-0 012 117; EP-A-0 306 547; EP-A-0 030 215; EP-A-0 272 824; EP-A-0 500 209; U.S. Pat. Nos. 4,996,323; 5,017,705; WO 97/05112; J. Het. Chem. 11 (1974), 889; J. Het. Chem 21 (1984), 97; Tetrahedron 41 (1985), 4057; Heterocycles 22,117; Synth. 1988, 938; J. Med. Chem. 25 (1982), 96, Chem. Pharm. Bull. 35 (1987), 2280 and WO 98/11071. The 2-aminopyridines of the formula XV can also be prepared from the corresponding pyridine derivatives which have carboxylic acid, carboxylic acid chloride, carboxylic acid azide, and carboxylic acid ester or carboxamide functions in the 2-position by Curtius, Hofmann or Lossen degradation reactions.
The reagents and starting compounds of the formulae V, VII, IX, IXa, X, Xa, XI, XII, XIIa, XIII, XIIIa, XVI, XVIIa, XVIIb, XVIIIa, XVIIIb, XIX, XXI, XXII, XXIV, XXIVa, XXVI, XXVII, XXVIII, XXX, XXXI, XXXIIIa, XXXIIIb and XXXIV which have been used in reaction schemes 1 to 9 are either known or can be prepared analogously to known processes.
The intermediates of the formulae III and IV 
in which R1, R2 and W have the meanings given under formula I, are novel. The invention thus also relates to these compounds.
The intermediates of the formula XVIIb 
in which R1, R2, R3 and X9 have the meanings given under formula I and R3 is additionally hydrogen are novel. The invention thus also relates to these compounds.
The reactions which give compounds of the formula I are advantageously carried out in aprotic, inert organic solvents. Such solvents are hydrocarbons such as benzene, toluene, xylene or cyclohexane, chlorinated hydrocarbons such as dichloromethane, trichloromethane, tetrachloromethane or chlorobenzene, ethers such as diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran or dioxane, nitrites such as acetonitrile or proprionitrile, amides such as N,N-dimethylformamide, N,N-diethylformamide or N-methylpyrrolidinone. The reaction temperatures are preferably between xe2x88x9220xc2x0 C. and +120xc2x0 C. In some cases, the reactions are slightly exothermic and, as a rule, they may be carried out at room temperature. To reduce the reaction time, or else to start up the reaction, the reaction mixture may be warmed briefly to boiling point, if appropriate. The reaction times may also be reduced by adding a few drops of base as reaction catalyst. Suitable bases are, in particular, tertiary amines such as trimethylamine, triethylamine, quinuclidine, 1,4-diazabicyclo-[2.2.2]-octane, 1,5-diazabicyclo-[4.3.0]-non-5-ene, 1,5-diazabicyclo-[5.4.0]-undec-7-ene or 4-dimethylaminopyridine. However, inorganic bases such as hydrides, e.g. sodium hydride or calcium hydride, hydroxides such as sodium hydroxide or potassium hydroxide, carbonates such as sodium carbonate or potassium carbonate, or hydrogen carbonates such as potassium hydrogen carbonate and sodium hydrogen carbonate, may also be used as bases.
The compounds of the formula I can be isolated in the customary manner by concentrating and/or by evaporating the solvent and purified by recrystallization or trituration of the solid residue in solvents in which they are not readily soluble, such as ethers, aromatic hydrocarbons or chlorinated hydrocarbons, or by means of column chromatography and a suitable eluent.
Suitable uses according to the invention of the compounds of the formula I or compositions comprising them are all application methods which are customary in agriculture such as, for example, pre-emergence application, post-emergence application and seed treatment, and a variety of methods and techniques, such as, for example, the controlled release of active ingredient. To this end, the dissolved active ingredient is applied to mineral granule carriers or to polymerized granules (urea/formaldehyde) and dried. If appropriate, an additional coating can be applied (coated granules) which allows controlled release of the active ingredient over a specific period.
The compounds of the formula I can be employed as herbicides as pure active ingredients, i.e. as obtained in synthesis. Preferably, however, they are processed in the customary manner with the auxiliaries conventionally used in the art of formulation, for example to give emulsifiable concentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granules or microcapsules. Such formulations are described, for example, in WO 97/34485 on pages 9 to 13. The application methods, such as spraying, atomizing, dusting, wetting, scattering or pouring, and the nature of the compositions are chosen to suit the intended aims and prevailing circumstances.
The formulations, i.e. the compositions, preparations or combinations which comprise the active ingredient of the formula I or at least one active ingredient of the formula I and, as a rule, one or more solid or liquid formulation auxiliaries, are prepared in the known manner, for example by intimately mixing and/or grinding the active ingredients with the formulation auxiliaries such as, for example, solvents or solid carriers. Furthermore, surface-active compounds (surfactants) may additionally be used when preparing the formulations. Examples of solvents and solid carriers are given, for example, in WO 97/34485 on page 6.
Suitable surface-active compounds are, depending on the nature of the active ingredient of the formula I to be formulated, non-ionic, cationic and/or anionic surfactants and surfactant mixtures which have good emulsifying, dispersing and wetting properties.
Examples of suitable anionic, non-anionic and cationic surfactants are listed, for example, in WO 97/34485 on pages 7 and 8.
The surfactants conventionally used in the art of formulation described in, inter alia, xe2x80x9cMcCutcheon""s Detergents and Emulsifiers Annualxe2x80x9d MC Publishing Corp., Ridgewood N.J., 1981, Stache, H., xe2x80x9cTensid-Taschenbuchxe2x80x9d [Surfactants Guide], Carl Hanser Verlag, Munic/Vienna, 1981, and M. and J. Ash, xe2x80x9cEncyclopedia of Surfactantsxe2x80x9d, Vol I-III, Chemical Publishing Co., New York, 1980-81 are furthermore also suitable for preparing the herbicidal compositions according to the invention.
As a rule, the herbicidal formulations comprise 0.1 to 99% by weight, in particular 0.1 to 95% by weight, of herbicide, 1 to 99.9% by weight, in particular 5 to 99.8% by weight, of a solid or liquid formulation auxiliary and 0 to 25% by weight, in particular 0.1 to 25% by weight, of a surfactant. While concentrated compositions are more preferred as commercially available goods, the end user uses, as a rule, dilute compositions. The compositions may also comprise other additives such as stabilizers, e.g. epoxidized or unepoxidized vegetable oils (epoxidized coconut oil, rapeseed oil or soya oil), antifoams, e.g. silicone oil, preservatives, viscosity regulators, binders, tackifiers and fertilizers or other active ingredients.
As a rule, the active ingredients of the formula I are applied to the plant or its environment at application rates of 0.001 to 4 kg/ha, in particular 0.005 to 2 kg/ha. The dosage required for the desired action can be determined by experiments. It depends on the type of action, the developmental stage of the crop plant and of the weed, and on the application (location, timing, method) and, due to these parameters, may vary within wide ranges.
The compounds of the formula I are distinguished by herbicidal and growth-inhibitory properties which allow them to be used in crops of useful plants, in particular in cereals, cotton, soya, sugar beet, sugar cane, plantation crops, oilseed rape, maize and rice and for non-selective weed control. Crops are also to be understood as meaning those which have been made tolerant to herbicides, or classes of herbicides, by conventional breeding or genetic engineering methods. The weeds to be controlled may be monocotyledonous or dicotyledonous weeds such as, for example, Stellaria, Nasturtium, Agrostis, Digitaria, Avena, Setaria, Sinapis, Lolium, Solanum, Echinochloa, Scirpus, Monochoria, Sagittaria, Bromus, Alopecurus, Sorghum halepense, Rottboellia, Cyperus, Abutilon, Sida, Xanthium, Amaranthus, Chenopodium, lpomoea, Chrysanthemum, Galium, Viola and Veronica.